Electrophotographic method for colored images

ABSTRACT

An electrophotographic method comprises developing an electric latent image formed on a photosensitive member comprising a photoconductive material and containing a first color forming agent in a surface for forming a visible image with a charged toner particle containing a second color forming agent, and heating to cause a thermal color forming reaction therebetween resulting in formation of a colored fixed image on the photosensitive member.

United States Patent [1 1 Nagashima et a1.

[ 1 Apr. 29, 1975 1 1 ELECTROPHOTOGRAPHIC METHOD FOR COLORED IMAGES [75] Inventors: Shinichiro Nagashima; Kaichi Tsuchiya; Yoshihiro Sakamoto; Hiroshi Yamakami. all of Tokyo; Seiji Tomari, Yokohama. all of Japan [73] Assignee: Canon Kabushiki Kaisha, Tokyo.

Japan [22] Filed: Sept. 28. 1972 [21] Appl. No.: 293,160

[30] Foreign Application Priority Data Oct. 2. 1971 Japan 46-77423 Oct. 5. 1971 Japan 46-78506 Oct. 5. 1971 Japan 46-78507 Oct. 5, 1971 Japan..... 46-78508 Oct. 26. 1971 Japan 46-84804 Nov. 25. 1971 Japan 46-94735 Dec. 6. 1971 Japan..... 46-98413 Jan. 31. 1972 Japan 47-11561 [52] U.S. Cl 96/11; 117/362 [51 Int. Cl G03g 9/02 [58] Field of Search 96/12; 117/362 Primary Examiner-Norman G. Torchin Assistant E.\'anzinerJohn L. Goodrow Attorney. Agent. or FirmFitzpatrick, Cella, Harper & Scinto [57] ABSTRACT An electrophotographic method comprises developing an electric latent image formed on a photosensitive member comprising a photoconductive material and containing a first color forming agent in a surface for forming a visible image with a charged toner particle containing a second color forming agent. and heating to cause a thermal color forming reaction therebetween resulting in formation of a colored fixed image on the photosensitive member.

20 Claims, 7 Drawing Figures PATENTEDAPR29IQ75 I I 3.880.656

2 FIG. I 2 w @m I 3 FIG. 2

4 060 k HEATING 3 FIG. 3 l OX 0 5 C: l $111111:

I 9 IO 7 FIG. 4 FIG. 5

FIG. 6

l6 I4 3 :llllllllgf l2 l7 II FIG. 7

- ELECTROPHOTOGRAPHIC,METHOD FOR COLORED IMAGES BACKGROUND OF THE INVENTION 1. Field of the Invention v This invention and the invention described in our copending US. Pat. application Ser. No. 305,672, filed Novnl3, 1972 relate to a novel color forming electrophotographic method utilizing a toner for electrostatic image containing a color forming agent (A) and a photoconductive photosensitive member or an image receiving sheet containing a color forming agent (B), and further to a} particular electrophotographic material used therefor. 7

2. Description of the Prior Art Here tofore, there have been known various electrophotographic processes such as those disclosed in US. Pat. No. 2,297,691, Japanese Patent Publication No. 23910/1967 and, Japanese Patent Publication No. 24748/1968. ln general, these electrophotographic processes comprise utilizing a photoconductive material, forming electric latent images on a photosensitive member, developing the latent images with a toner, if desired, transferring the developed image to an image receiving sheet such as paper and fixing the transferred image by heating or with solvent vapor.

It is .widely: known to use, as a developing toner, finely divided particles of l 20 microns in diameter composed of a coloring pigment such as carbon black dispersed in a binder resin such as styrene resin. Such a toner is usually mixed with a carrier material such as glass beads, iron powder, fur and the like, or dispersed in an insulating liquid. and then attracted to or repulsed by the electrostatic latent image to visualize the negativeor positive electric image.

The above-mentioned prior arts have the following two problems. One is smudging during manufacturing and developmentsince the toner is finely divided black powder. Such finely divided toner is so light that the toner is easily blown up to dirty remarkably hands, feet and clothes as well as room, and further to cause dust pollution outdoors. Dry toner is particularly of high contrast and gives images of high quality, but this dirt problem reduces the usefulness of dry toner.

The other is concerned with fixation. In general, toner is fixed by heating, but when a switch is turned on and then immediately the reproduction operation starts, fixation of the resulting image is incomplete and when rubbed, the toner is easily removed. Thus, the fixed portion is preliminarily heated and brought to a sufficient temperature, and then the reproduction operation can start. Particularly, a necessary preliminary heating time is usually 10 minutes for dry reproduc' tion machine, and when once the machine is switched on, the fixed device should be kept at a constant temperature until the business time is finished.

As an electrophotographic method using a color forming system, there may be mentioned that disclosed in Japanese Patent Publication No. 15912/1966 which comprises covering a diazonium compound with wax and the like and combining with a paper coated with a coupler, that disclosed in Japanese Patent Publication No. 989/1967 and Japanese Patent Publication No. 3837/1970 which comprises using a volatile first chemical material as toner and a'second chemical material (metal salt) as a reproduction sheet to form a colored image. However, when a diazonium compound is used as toner, there is disadvantageously a danger of explo sion during pulverizing procedure and further and alkali treatment is necessary upon forming color, and therefore, it is not practical. Furthermore, in a system 5 using a metal salt it is difficult to obtain clear and sharp color.

SUMMARY OF THE INVENTION An object of this invention is to provide an electrophotographic method which can solve the abovementioned drawbacks of prior art and in which a toner is colorless or of light color and a completely fixed image can be obtained without any waitingtime.

Another object of this invention is to provide a novel multicolor electrophotographic method comprising forming an image on an image receiving sheet containing a color forming agent (B) infra by using a toner for electrostatic image containing a color forming agent (A) infra and applying a color forming treatment to form a visible image.

A further object of this invention is to provide a colorless or light color toner for electrostatic image containing a color forming agent (A) infra which can form color by heating together with a color forming agent (B) infra.

Still anothher object of this invention is to provide an electrophotographic photosensitivemember containing a color forming agent (B) infra capable of forming color by reacting with a color forming agent(A) infra contained in a toner for electrostatic image.

A still further object of this invention isto provide an image receiving sheet containing a color forming agent (B) infra used for transferring an image formed by a toner for electrostatic image containing a color forming agent (A) infra.

Still another object of this invention is to provide an electrostatic transferring paper containing 'a color forming agent (B) infra.

According to this invention, there is provided an electrophotographic method which comprises developing an electric latent image formed on a photosensitive member comprising a photoconductive material and containing a color forming agent (B) in a surface for forming a visible image with a charged toner particle containing a color forming agent (A), and heating to cause a thermal color forming reaction between the color forming agent (A) in the toner and the color forming agent (B) in the photosensitive member resulting information of a colored fixed image on the photosensitive member, the color forming agent (A) being selected from the group consisting of 1. diarylphthalides,

2. leuco auramines,

. acryl auramines,

. call-unsaturated arylketones,

basic monoazo dyestuff,

. rohdamine B lactams,

. polyarylcarbinols,

. benzoindolino spiropyranes,

. phthalans, and

10. spirophthalans, and the color forming agent (B) being selected from 5 the group consisting of 1. polymer of phenol and aldehyde, 2. polymer of phenol and acetylene, 3. rosin modified maleic acid resin,

4. hydrolyzed product of copolymer of stryrene and maleinic anhydride,

5. hydrolyzed product of polymer of carboxy polyethylene,

6. hydrolyzed product of copolymer of vinyl methyl ether and maleic anhydride,

7. hydrolyzed product of copolymer of ethylene and maleic anhydride,

8. Japanese acid clay,

9. bentonite,

10. diatomaceous earth,

ll. bisphenol compounds containing carboxyl radical in a molecule,

12. polymers of bisphenol compounds containing carboxyl radical in a molecule, and

13. phenolic material.

According to another aspect of this invention, there is provided an electrophotographic method as mentioned above in which the toner particle contains the color forming agent (A) and a color forming auxiliary agent having a melting point ranging from 40 to 130 C selected from the group consisting of fatty acid, fatty acid metal salt, fatty acid ester, fatty acid amide, fatty acid anilide and solid plasticizer.

According to a further aspect of this invention, there is provided an electrophotographic method as mentioned above in which the visible image forming surface of the photosensitive member contains the color forming agent (B) and a color forming auxiliary agent having a melting point ranging from 40 to 130 C selected from the group consisting of fatty acid, fatty acid metal salt, fatty acid ester, fatty acid amide, fatty acid anilide and solid plasticizer.

According to still another aspect of this invention, there is provided an electrophotographic method which comprises developing an electric latent image formed on a photosensitive member comprising a photoconductive material with a charged toner particles containing a color forming agent (A), transferring the resulting toner image to an image receiving sheet containing a color forming agent (B), and heating to cause a thermal color forming reaction 'between the color forming agent (A) in the toner and the color forming agent (B) in the photosensitive member resulting in formation of a colored fixed image on the image receiving sheet.

According to a still further aspect of this invention, there is provided an electrophotographic method as mentioned above in which the toner particle contains the color forming agent (A) and a color forming auxiliary agent having a melting point ranging from 40 to 130 C selected from the group consisting of fatty acid, fatty acid metal salt, fatty acid ester, fatty acid amide, fatty acid anilide and solid plasticizer.

According to still another object of this invention, there is provided an electrophotographic method as mentioned above in which the visible image forming surface of the photosensitive member contains the color forming agent (B) and a color forming auxiliary agent having a melting point ranging from 40 to 130 C selected from the group consisting of fatty acid, fatty acid metal salt, fatty acid ester, fatty acid amide, fatty acid anilide and solid plasticizer.

According to a still further aspect of this invention, there is provided an electrostatic recording method which comprises developing an electric latent image formed on an electrostatic recording paper containing a color forming agent (B) in the visible image forming surface with a charged toner particle containing a color forming agent (A), and heating to cause a thermal color forming reaction the color forming agent (A) in 5 the toner and the color forming agent (8) in the electrostatic recording paper resulting in formation of a colored fixed image.

According to still another aspect of this invention, there is provided an electrostatic recording method as mentioned above in which the toner particle contains the color forming agent (A) and a color forming auxiliary agent having a melting point ranging from 40 to 130 C selected from the group consisting of fatty acid, fatty acid metal salt, fatty acid ester, fatty acid amide, fatty acid anilide and solid plasticizer.

According to a still further aspect of this invention, there is provided an electrostatic recording method as mentioned above in which the visible image forming surface of the photosensitive member contains the color forming agent (B) and a color forming auxiliary agent having a melting point ranging from 40 to 130 C selected from the group consisting of fatty acid, fatty acid metal salt, fatty acid ester, fatty acid amide, fatty acid anilide and solid plasticizer According to still another aspect of this invention, there is provided a recording method which comprises closely contacting a master sheet having a toner image containing a color forming agent (A) with a visible image forming surface containing a color forming agent (B) of an image receiving sheet and heating to cause a thermal color forming reaction between the color forming agent (A) and the color forming agent (B) resulting in a visible image.

According to a still further aspect of this invention, there is provided a recording method as mentioned above in which the toner image contains the color forming agent (A) and a color forming auxiliary agent having a melting point ranging from 40 to 130 C selected from the group consisting of fatty acid, fatty acid metal salt, fatty acid ester, fatty acid amide, fatty acid anilide and solid plasticizer.

According to still another aspect of this invention, there is provided a recording method as mentioned above in which the visible image forming surface of an image receiving sheet contains the color forming agent (B) and a color forming auxiliary agent having a melting point ranging from 40 to 130 C selected from the group consisting of fatty acid, fatty acid metal salt, fatty acid ester, fatty acid amide, fatty acid anilide and solid plasticizer.

According to a still further aspect of this invention, there is provided a toner for electrostatic image which comprises containing in a binder resin a color forming agent (A) selected from the group consisting of diarylphthalides,

. leuco auramines,

. acryl auramines,

. a,B-unsaturated arylketones. basic monoazo dyestuff,

. rohdamine B lactams,

. polyarylcarbinols,

. benzoindolino spiropyranes, phthalans, and

10. spirophthalans.

According to still another aspect of this invention, there is provided a toner for electrostatic image as mentioned above in which the binder resin contains the color forming agent (A) and a color forming auxiliary agent having a melting point ranging from 40 to 130 C selected from the group consisting of fatty acid, fatty acid metal salt, fatty acid ester, fatty acid amide, fatty acid anilide and solid plasticizer.

According to a still further aspect of this invention, there is provided an electrophotographic photosensitive member which comprises a photoconductive material and a visable image forming surface of the photosensitive member containing a color forming agent (B) selected from the group consisting of 1. polymer of phenol and aldehyde,

2. polymer of phenol and acetylene,

3, rosin modified maleic acid resin,

4. hydrolyzed product of copolymer of styrene and maleic anhydride,

5. hydrolyzed product of polymer of carboxy polyethylene,

6. hydrolyzed product of copolymer of vinyl methyl ether and maleic anhydride,

7. hydrolyzed product of copolymer of ethylene and maleic anhydride,

8. Japanese acid clay,

9. bentonite,

l0. diatomaceous earth,

1 l. bisphenol compounds containing carboxy] radical in a molecule,

12. polymers of bisphenol compounds containing earboxyl radical in a molecule, and

13. phenolic material.

According to still another aspect of this invention, there is provided an electrophotographic photosensitive member as mentioned above in which the visible image forming surface of the photosensitive member contains the color forming agent (B) and a color forming auxiliary agent having a melting point ranging from 40 to 130 C selected from the group consisting of fatty acid, fatty acid metal salt, fatty acid ester, fatty acid amide, fatty acid anilide and solid plasticizer.

According to a still further aspect of this invention, there is provided an image receiving sheet which comprises a visible image forming surface containing a color forming agent (B) selected from the group consisting of l. polymer of phenol and aldehyde,

2. polymer of phenol and acetylene,

3. rosin modified maleic acid resin,

4. hydrolyzed product of copolymer of styrene and maleic anhydride,

5. hydrolyzed product of polymer of carboxy polyethylene,

6. hydrolyzed product of copolymer of vinyl methyl ether and maleic anhydride,

7. hydrolyzed product of copolymer of ethylene and maleic anhydride,

8. Japanese acid clay.

9. bentonite,

10. diatomaceous earth,

' 11. bisphenol compounds containing carboxyl radical in a molecule,

12. polymers of bisphenol compounds containing carboxy] radical in a molecule, and

13. phenolic material,

According to still another aspect of this invention, there is provided an image receiving sheet as mentioned above in which the visible image forming surface contains the color forming agent (B) and a color forming auxiliary agent having a melting point ranging from 40 to C selected from the group consisting of fatty acid, fatty acid metal salt, fatty acid ester, fatty acid amide, fatty acid anilide and solid plasticizer.

According to a still further aspect of this invention, there is provided an electrostatic recording paper which comprises a support layer and an' electrostatic recording layer overlying the support layer and containing a color forming agent (B) selected from the group consisting of l. polymer of phenol and aldehyde,

2. polymer of phenol and acetylene,

3, rosin modified maleic acid resin,

4. hydrolyzed product of copolymer of styrene and maleic anhydride,

5. hydrolyzed product of polymer of carboxy polyethylene,

6. hydrolyzed product of copolymer of vinyl methyl ether and maleic anhydride,

7. hydrolyzed product of copolymer of ethylene and maleic anhydride,

8. Japanese acid clay,

9. bentonite,

10. diatomaceous earth,

ll, bisphenol compounds containing carboxyl radical in a molecule.

12. polymers of bisphenol compounds containing carboxyl radical in a molecule, and

13. phenolic material.

According to still another aspect of this invention, there is provided an electrostatic recording paper as mentioned above in which the electrostatic recording layer contains the color forming agent (B) and a color forming auxiliary agent having a melting point ranging from 40 to 130 C selected from the group consisting of fatty acid, fatty acid metal salt, fatty acid ester, fatty acid amide, fatty acid anilide and solid plasticizer.

BRIEF. DESCRIPTION OF THE DRAWINGS FIG. 1 shows diagrammatically a conventional fixing procedure;

FIG. '2 shows diagrammatically a color forming and fixing procedure according to the present invention;

FIG. 3 shows a fixing apparatus;

FIG. 4 shows diagrammatically a cross sectional view of a master sheet according to the present invention;

FIG. 5 shows diagrammatically a cross sectional view of a printing member used in the present invention;

FIG. 6 shows diagrammatically a procedure for reproducing an image by using a master sheet of FIG. 4 and a printing member of FIG. 5; and

FIG. 7 shows diagrammatically a reproduction abtained in FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Mala- 7 N-alkylhalophenyl derivatives, N-(2,5-dichlorophenyl leuco auramine, *and the like. 1 3. Acryl auraminesr N-benzoyl auramine, N-acetyl auramine,-and the like.

.4.- a,/3-unsaturated arylketones:

. Dianisylidene acetone,

Dibenzylidene acetone, Anisylidene acetone, and the like. 5. Basic monoazo dye:

p-dimethylaminoazobenzene-O-carboxylic acid I (Methyl Red),

4-aminoazobenzene (Oil Yellow AAB), 4-phenylazo-1-naphthylamine, and the like.

6. Rohdamine B lactams:

N (p-nitrophenyl) rohdamine B lactam, 3,6'-diamino rohdamine B lactam, 3,6'-diethylamino rohdamine B lactam, 3,6'-dimethylamino rohdamine B lactam, and the like.

7. Polyaryl carbinols Bis-(p-dimethylaminophenyl) methanol (Michlers hydrol),

Crystal Violet Carbinol, Malachite Green Carbinol, and the like.

8. Benzoindolino spiropyrans:

8"-methoxy benzoindolino spiropyran, 4,7 ,8trimethoxy benzoindolino spiropyran, 6 -chloro-8'-methoxy benzoindolino spiropyran and the like.

.9. Phthalans:

l, 1 -bis( p-aminophenyl) phthalan, 1,1-bis(p-benzylaminophenyl) phthalan, I l,l-bis(p-dibenzylamino phenyl) phthalan, 1,1-bis(p-N-methylanilino phenyl) phthalan, and the like.

i 10. Spirophthalans:

6,6'-dia minospiro (phthalan-l,9'-xanthen) 6,6'-diethylaminospiro (phthalan-l ,9-xanthen) 6,6'-dimethylaminospiro (phthalan- 1 ,9-xanthen) and the like.

These color forming agents (A) can react with the color forming agent (B) as mentioned above to form color. These materials are disclosed in Japanese Patent Publication Nos. 10788/1965, 9309/1965, 9310/1965, 3257/1967, 9071/1969, 10318/1969 and 11634/1969.

Among the color forming agents (B) used in this invention, examples of (l l) bisphenol compounds containing carboxyl radical in a molecule are:

(3H2 l... I

'OOII (mp. 90 C.) (1) and 1[O OH I (100m (mp. 85 (1. 2

Further, examples of (12) polymers of bisphenol compounds containing carboxyl radical in a molecule are:

(Softening point 96 109 C, overage degree of polymerization 4O 45). These bisphenol compounds are preferable color forming agents (B).

Furthermore, examples of (B) phenolic material are shown below:

4-tertiary-butyl phenol, 4-B-tertiary-amyl phenol, 4-phenyl phenol, 4,4-isopropylidene-bisr(2-chloro phenol), 4,4'-isopropylidene-bis-(Z-rnethyl phenol), 4,4'-isopropylidene-bis-(2-tertiary butyl phenol), 4,4-secondary-butylidene-bis-( Z-methyl phenol), 2,2-dihydroxy diphenyl, 4,4-secondary butylidene diphenol, 4-tertiary-octyl catechol, 4-hydroxy aceto phenone, methyl-4-hydroxy benzoate,

4-hydroxy diphenoxide, a-naphthol, B-naphthol, 4-hydroxy diphenyl oxide, 2,2'-methylene-bis-(4-chloro phenol), 2,2'-methylene-bis-(4-methyl-6-tertiary-butyl nol, 4,4'-isopropylidene-bis(2,6-dibromo phenol), 4,4'-isopropylidene-bis-(2,6-dimethyl phenol), 4,4'-cyclohexylidene diphenol, 4,4-cyclohexylidene-bis-( 2-methyl phenol). The reaction of the color forming agent (A) and the color forming agent (B), a kind of base-acid reactions, according to the present invention, is illustrated by using a combination of malachite green lactone and phenolic resin as an example.

phe-

' 1)]10110110 resin Conventional electrophotographic methods are applicable to the production of electric latent image in the present invention. For example, there may be mentioned conventional electrophotographic methods such as Carlson process comprising charging a whole surface of photoconductive layer composed of selenium, CdS or ZnO and then projecting a light image to form a latent image and a method disclosed in Japanese Patent Publication No. 23910/1967 or 24748/1968 comprising uniformly charging a photosensitive member composed of a photoconductive layer such as selenium and CdS and an insulating layer such as polyester overlying the photoconductive layer, applying corona charging simultaneously with imagewise exposure, and applying blanket exposure.

The latent image thus obtained may be developed by a conventional developing method such as cascade developing methods, magnetic brush developing methods. fur brush developing'methods and liquied developdeveded particle as toner to form an, image, but the chargeability is poor and fog forms, and moreover,

color forming property is poor. Furthermore, there is formed sometimes are image composed of both negative and positive images. The thermal conductivity is so low that melting by heating is not sufficient and color forming efficiency is poor and the density of the resulting image is low. High fixing temperature is necessary and further, the color forming dye directly contacts atmosphere to cause deterioration of the color forming agent (A) due to moisture and oxygen.

The present inventors have successfully eliminated such disadvantages by dispersing the color forming agent (A) in a resin of relatively low me'ltingpoint such as from to 130 C which hasbeen used as a binder resin for an electrophotographic toner' such. as vinsol resin, cumarone resin, polystyrene: polyvinyl acetate, polyvinyl chloride, polyethylene, polyacrylic acid ester, polyvinyl acetal, polyvinylidene chloride, polyethylene terephthalate, alkyd resin, polyamide resin, epoxy resin, polypropylene, mixtures thereof, and copolymers thereof, the resulting toner for development has a highly improved chargeability.

For the purpose of improving furtherfcolor forming efficiency and low temperature fixing efficiency, the color forming agent (A) and the binder resin are sufficiently melted at a certain temperature to cause a reaction with the color forming agent (B) on the photosensitive member or the transferring supportllt has been now found that addition of a color' forming auxiliary agent capable of low temperature fixation and improving the image density to attain the purpose.

The color forming auxiliary agent has a melting point ranging from 40 to 130 C selected from the group consisting of fatty acid, fatty acid metalfsalt, fatty acid ester, fatty acid amide, fatty acid anilide and solid plasticizer. These color forming auxiliary agent are mutually soluble with a binder resin, a color forming agent (A) and a color forming agent (B).

Representative color forming auxiliary agents are as shown below.

1. Fatty acids compounds. for example,

The numbers in the parenthese are melting points. The preferable color forming auxiliary agents are fatty acids containing 12 and more than of carbon atoms and having melting points ranging from 40 to C.

2. Metallic salts of fatty acids having melting points ranging from 40 to C are shown by the following general formula:

(R C O O),,M

wherein n =1 3; M is Be, Mg, Ba, Zn, Cd, Hg, A1, T1, Pb and the like; R is an alkyl radical.

Representative examples are as follows:

Lead caproate (m.p. 73 74 C) Lead enanthate (m.p. 78 C) Lead eaprylate (m.p. 88 84 C) Lead pelargonate (m.p. 94 95 C) Lead caprate (mup. 100 C) Lead laurate (m.p. 106 C) Lead'myristate (m.p. 108.6 C) Lead palmitate (m.p. 1 12 C) Lead stearatc (m.p. 1 16 125 C) Lead trideeylatc (m.p. 128 C) Aluminum stcarate (m.p. 105 C) Beryllium stearatc (m.p. 45 C) 3. Fatty acid derivatives having melting points ranging from 40 to 130 C, which are represented by the following formula:

where R is alkyl; R is alkyl or aryl. Representative examples are as follows:

(i) Methyl esters:

Methyl araehinate (m.p. Methyl behenatc (m.p. 54 C) Methyl lignocerate (m.p. 56.7 57 C) Methyl cerotinatc (m.p. 63 C) Methyl heptacosanate (m.p. 64 C) Methyl montanate (m.p. 685 C) Methyl melissinate (m.p. 7 1 .5 C) (ii) Ethyl esters:

, Ethyl arachinate (m.p. 42 C) Ethyl behcnate (m.p. 50 C) Ethyl lignocerate (m.p. 56.7 57 C) Ethyl eerotinate (m.p. 60 C) Ethyl montanate (m.p. 64 65 C) Ethyl melissinate (m.p. 70.5 C) Ethyl laccerate (m.p. 76 C) (iii) Phenyl esters:

Phenyl arachinate (m.p. 58.5 C) Phenyl palmitinatc (m.p. 45 C) (i\') Glycohol esters:

Glycohol myristate (m.p. 64 C) Glycohol palmitinate (m.p. 51.5 C) Glyeohol stearate (m.p. 58 75 C) (v) Glycerol esters Glycerol laurate (m.p. 63 C) Glycerol myristatc (m.p. 56 70.5 C) Glycerol palmitinate (m.p. 34 77 C) Glycerol stearate (m.p. 54 71 C) 4. Fatty acid derivatives having melting points ranging from 40 C to 130 C, which are represented the following formula where R is alkyl; R and R is H, alkyl, or aryl. Representative examples useful for this invention are as follows:

( Amidcs:

Acetic amides (m.p. 82 83 C) Propionic amide (m.p. 818C) Butyrie amide (mp. 115 1 16C) Valerie amide (m.p. 106C) Caproic amide (m.p. 101C) Enantic amide (m.p. 93 94C) Caprinic amide (m.p. 105.9C) Peralgonoic amide (mp. 989C) Undecylic amide (m.p. 84.5 855C) Laurie amide (m.p. 102.4C) Tridecylic amide (m.p. 100C) Myristie amide (m.p. 105.1C)

' -Continued Pentadecylie amide (m.p. 102C) Palmitic amide (m.p. 107C) Heptadccylic amide (m.p. 108 109C) Stearic amide (m.p. 109.7C) Arachic amide (m.p. 108C) Behenie amide (m.p. 1 1 1 1 1 12C) Cerotic amide (m.p. 109C) Montanic amide (m.p. 1 12C) (ii) Anilides:

Valerie anilide (m.p. 68C) Caproic anilide (m.p. 92C) Caprylic anilide (m.p. 55C) Pcralgonoic anilide (m.p. 575C) Capric anilide (m.p. 625C) Undecylie anilide (m.p. 71C) Laurie anilide (m.p. 77.2C) Myristie anilide (m.p. 84C) Palmitic anilide (m.p. 902C) Stcarie anilide (m.p. 94C) Behenic anilide (m.p. 101 102C) (iii) N-Methyl amides Capric methyl amide (m.p. 578C) Laurie methyl amide (m.p. 62.4C) Myn'stic methyl amide (m.p. 784C) Palmitie methyl amide (m.p. 855C) Stearie methyl amide (m.p. 921C) (iv) N-Dodeeylic amides Laurie dodeeyl amide (m.p. 77 775C) Myristic dodeeyl amide (m.p. 84 C) Palmitic dodeeyl amide (m.p. 82.5 85C) Stearic dodeeyl amide (m.p. 85 855C) 5. Solid plasticizers, for example, diphenyl phthalate, dicyclohexyl phthalate, ethylene glycol dibenzoate, and dimethyl isophthalate.

Addition of the color forming auxiliary agent results in high color forming efficiency, good low temperature fixation, and colored image copy having sharp and sufficient density. Such improvement is considered due to that the color forming auxiliary agent melts at relatively low temperature and the color forming agent (A) and the binder resin and further the color forming agent (B) in the photosensitive member or transferring paper are mutually soluble with the color forming auxiliary agent to cause coloring and fixing at a low temperature and enhance the color forming density.

It has been further found from experiments shown later that the color forming auxiliary agent gives a good result when the color forming auxiliary agent is added together with the color forming agent (B) to a visible image forming surface of the eleetrophotographic photosensitive member or image receiving sheet.

The amount of the color forming auxiliary agent is usually more than 5 parts preferred with 20 200 parts, particularly preferred with 30 150 parts, per parts of the color forming agent. (A).

Now referring to FlG. 1 and FIG. 2, there is explained the difference between coloring and fixation of the present invention and fixation of conventional dry electrophotographic method. According to conventional method, a toner image 2 formed on a support 1 such as paper is already colored before heat-fixation and can be fixed to support 1 by heat-fixing at relatively high temperature. On the contrary, according to the color forming fixing method of the present invention, a color forming agent layer 4 is formed on a support 1 such as paper and a toner image 3 containing a color forming agent (A) formed on the color forming agent layer 4 is colorless or of light color. When these are heated at a relatively low temperature and melted to cause'a color forming reaction with a color forming agent-(B) layer 4 resulting in the colored portion 30. As is clear from above, a conventional toner image is often removed by rubbing while a colored image according to the present invention is not removed at all by rubbing.

Conventional dry toner (thermoplastic resin carbon system) is compared with the toner of the present invention (Example 1 with respect to fixing temperature by using a fixing apparatus as illustrated in FIG. 3.

As shown in FIG. 3, four 250W infrared heaters are arranged and a conveyor 8 of 200 mm long moves at 123 mm/sec. and a transferring sheet moves thereon to Fixing temperature Conventional toner This result indicates that waiting time of a copier can be shortened to a great extent.

The following experimental examples are given for illustrating the improvement accomplished by the present invention. In the experimental examples, ingredients are mixed at the weight ratio as listed in the following tables and melted and cooled, and then pulverized 5 ducted as shown below.

1. State at normal temperature after mix-melting:

Distinguishing solid mater and sticky semi-solid by naked eyes. 2. Pulverizing property:

form color andfix. Referernce numbers 6, 7, 8, 9 and i0 Degree of pulverizing property is designated as devote a heat insulating material, a gear, a wire net shown below; conveyor, a thermometer and a variable thermostat, good respectively. O fairly good By using this fixing apparatus, each fixing tempera- A somewhat bad ture was measured. X bad 3. Maximum color forming density, Fog density:

Reflective density is measured by MACBETH quantalog densitometer RD-l00 with a red filter.

4. Image blur, resolving power:

Evaluation of images on a transferring paper by naked eyes and the evaluation results are designated in the same way as shown in item 2 above.

5. Chargeability:

Mixing an iron powder carried with a sample toner and measuring polarity of charge, negative or positive.

6. Fixing temperature:

Measured by a method as mentioned above. In the by using a jet mill to form a toner of less than 20 mif ll i bl 1)-1 25 denotes polystyrene crons in size. Ten parts by weight of the resulting toner pli d by E550 Standard Co. (trade name, Piccolaswas mixed with 90 parts by weight of iron powder of ti 1)-] 25") a d CVL denotes Crystal Violet microns in size, and image formation was effected by Lactone.

TABLE 1 Experiment Number 1 2 3 4 5 6 7 8 9 10 11 12 13 14 D425, parts .s 25 50 70 70 70 70 7O 70 70 7O 70 70 Stearw acid, parts. 5 10 20 30 40 15 15 15 15 15 CV L, parts Y 30 30 30 30 30 5 10 20 40 60 State after fusing at room temperature Solid Solid Solid Solid Solid Solid Solid Solid Solid Solid Solid Solid Solid Solid l'ulverizing property A O Fusing to drum... None None None None None None None A little Exist None None None None A little Charge al ility Fixing temperature, C 300 290 280 270 200 185 175 170 200 220 Maximum density of lomed colon. 0. 3 0.3 0.2 0.2 0. 6 0.8 1. O 1.05 1.0 0. 8 1. 0 1.0 1.0 1.0 Density of fog 0. 1O 0. 01 0. 02 0. 03 0. 04 0. 05 0. 07 0. 02 l). 03 O. 03 0. 05 0. 08 Blur" None None None A little Exist None None None None A little Resolving power. A O O O O O O O Total evaluation A A O O O A A O O A TABLE 2 Experiment number 15 16 17 18 19 20 21 22 23 24 1)125, parts 70 7O 70 70 70 7O 70 7O 70 70 Miiystie acid, parts 5 10 20 30 40 15 15 15 15 15 OVL, parts .s 30 30 30 30 30 5 10 20 40 60 State alter fusing at 100111 temperatui Solid Solid Solio Solid Solid Solid Solid Solid Solid Solid lulvei'izing property O A O O Fusing to drum None None None A little Exist None None None None A little (Jhargvability Fixing temperature, C 210 205 190 180 170 175 180 180 195 Maximum density of formed color 0. 6 0. U 1.0 1. 05 1. 0 0. 8 1. 0 1.02 1. 0 1. 10 Density of fog O. 02 O. 03 0. 03 0. 05 O. 17 0. 02 0. 03 0. 03 0. 05 07 Blur None None None A little Exist None None None None A little Resolving power O O O O O Total evaluation O O A O A TAB L E 3 Experiment number 2a 26 27 28 29 30 31 32 33 34 ])125, parts 70 70 70 70 70 70 70 70 70 70 Aluminum stearate, parts 5 10 20 30 40 15 15 15 15 15 (."VL .1 30 30 3O 30 30 5 10 20 40 60 lulverizing pi'ope O A X O O Fusing to (1111111.. None None None A little Exist None None None None A little (hargeahility f Fiu'ng lenipvi'atu 215 200 185 180 185 190 215 235 Maumnni density of foiintt 0. 5S 0. 81 1. J7 1.00 1.02 0. 79 1.01 1. 00 1.01 1.03 Density of fog 0. 02 0. 03 0. 04 0. 05 0. O7 0. 02 0. 03 0. 03 0. 05 08 Blur None None None A little Exist 7 None None None None A little Resolving, power GD O 3) O O Total evaluation O A A O O A .TABLE 4 Experiment number w 35 36 37 38 39 40 41 42 43 44 45 46 47 48 X Fusing to druin None None None None A little Exist None None None N08: A litt Chargealjility Fixing temperature, C 300 290 280 270 210 195 185 180- 175 v 180 185 190 210 v 230 Maximum density of forrneu eolor 0.27 0.30 0. 2O 0. 25 0. 63 O. 87 1. 09 1. 05 1. 00 0.81 1. 02 1. 05 1. 00 1. 07 Density of fog O. 01 0.01 0. 01 0. 01 0.02 0. 03 0. 04 0. 04 0.08 0.02 0. 03 0.03 0. 05 4 0. 08 Blur Exist Exist None None None None None A little Exist None None None None A little Resolving power... A A O O O O O O Q Q Total evaluation .1.... A A O O O A A O Q A TABLE 5 Experiment number 49 50 51 52 53 54 55 56 57 58 59 60 61 62 l)l25, parts 25 50 70 85 70 70 70 70 70 70 70 70 70 70 Glycol stearate, parts 5 10 20 30 40 15 15 15 p 15 15 CVL, parts 75 50 3O 15 30 30 30 30 30 5 10 20 40 60 lulverizing property A 0 A 0 Q Fusing to drum None None None None None None None A little Exist None None None None A. little Cliargeability 1 Fixing temperature, C 300 290 280 270 200 185 175 170 165 170 175 180 200 220 Maximum density of formed color 0. 32 O. 31 0. 20 0. 21 0. 61 0. 83 0. 95 1. 01 1. 00 0.85 1. 01 1.01 1.01 1. 00 Density of fog 0. 01 0. 01 0.01 0.01 0.02 0.03 O. 03 0. 05 0.07 0.02 0.03 0. 03 0.05 0.08 Blur Exist Exist None None None None None A little Exist None None None None A little Resolving power A A O O O O O O Q Total evaluation A A O O O (D A A O O- A TABLE 6 Experiment number 63 64 65 66 67 68 69 70 71 7 2 D125, parts 70 70 70 70 70 p 70 70 70 70 70 Glycol stearate, parts 5 10 20 30 40 15 15 15 15 15 CVL, parts 30 30 30 30 30 v 5 10 2O 40 60 Pulverizing property O A X O Fusing to drum None None None A little Exist None None None None A little Chargeability Fixing temperature, C 205 190 180 175 170 175 180 185 .205 225 Maximum density of formed color 0. 60 0.80 1.00 1. 05 1.00 O 80 1. 01 1.00 1. 00 1 00 Density of fog 0. 02 0. 03 0. 04 0. 05 0. 07 0 02 0. 03 0. 03 0. 05 0. 08 Blur None None None A little Exist None None None None A little Resolving power O O O O Total evaluatioiLr O A A O I O A TABLE 7 Experiment number 73 74 75 76 77 78 79 80 81 82 D-125, parts 70 70 70 70 70 70 70 70 70 70 .Methyl behenate, parts. 5 10 20 30 40 15 15 15 15 15 CVL, parts 30 30 30 30 30 5 10 20 40 60 Pulverizing property. O 1 Fusing to drum. None None None A little Exist None None None None A little Chargeability Fixing temperature, C 190 175 165 160 155 160 1&5 170 190 210 Maximum density of formed color 0.53 0. 80 0 95 1. 00 1. 01 0.81 1.01 1 00 1. 00 1 00 Density of fog 0. 02 O. 03 0 01 0. 05 0. 07 0.02 O. 03 0. 03 0 O5 0 Blur None None None A little Exist None None None None A little Resolving power. O O O Total evaluation O A A O O A TABLE 8 Experiment number L 83 84 85 86 87 88 89 90 91 J2 D-125, parts- 70 70 70 70 70 70 70 70 70 70 Ethylbehenate, parts 50 10 2O 30 40 15 15 15 15 15 CVL, parts 30 30 30 30 30 5 10 Y 20 40 60 lulverizing property 0 A X O O Fusing to drum None None None A little Exist None N one None None A little Chargeability Fixing' temperature, C 190 175 165 160 210 Maximum density of formed eolor O. 60 0. 7.) 1.00 1. 01 1.00 0. 80 1.01 1.01 1. 00 1.00 Density of log 0.02 0. 03 0. 04 0. 05 0.07 0. 02 0. 03 0. 03 0.05 08 Blur None None None A little Exist None None None None A little Resolving power O O O O Total evaluation O A A O O A TABLE fl Experiment number 93 94 95 96 97 98 99 100 101 102 103 104 105 106 D-125, parts 25 50 70 85 70 70 70 70 70 70 70 70 70 70 Leurie amide, parts 5 10 20 30 40 15 15 15 15 15 OVL, parts- 75 50 30 15 30 30 30 30 30 5 10 20 40 60 lulverizing property A O A X O O Fusing to drum None None None None None None None A little Exist None None None None A little Chargeziliility Y Fixing temperature, C 300 200 280 270 225 110 200 185 10.1 200 205 225 245 Maximum density. of formed -olor. 0.30 0.30 0.20 O. 20 (1.60 0. 8t) 1. 00 1. 05 1.01 0. 8 1. 00 1. 02 1.01 1. 00 Density of fog 0.01 0.01 0. ()1 0.01 0 02 0. 03 0. 04 0. 05 0.07 0. 02 0.03 0.03 0.05 0.08 Blur Exist Exist None None N one None None A little Exist None None None None A little Resolving power A A O O O A O 6 O O A A O O O A A O O A Total evaluat ion TABLE Ex nn'imcnt number 107 108 100 110 111 112 113 114 115 116 D 12 parts..- I 70 70 70 70 70 70 70 70 70 70 Lnuno amlulegpa s. 5 1O 20 30 40 10 40 60 ()VL. parts 30 30 30 30 15 10 20 lulvorizingproperty. I Q A 1 Q Q Fusing io (l rum. None None None A little Exist Nonev None None None A little (hargealnhty. 1 4 1 Fixing tempera 1. 200 180 175 170 165 0 175 180 200 220 0.57 0.81 1.05 1.01 1.00 0. 87 0.95 1.03 1.05 1.01 0. 0'1 0. 02 0. 04 0.01 0.07 0. 02 0.03 0. 04 ,0. 05 0. 07 v None None None A little. Exist None None None. [None A little Resolving DOWtL O O O Q Q Q Total evaluation O G) A A 0 0: A

TABLE 11 Experiment number 117 118 120 121 122 123 124' j 125 12s 'l)-l25, pnrts 70 70 70 70 70 20 70 .70 70 70 Leurio N-melhylamide, parts 5 10 20 30 40 15 15 15 15 15 (TV L, parts 30 30 30 30 30 5 10 20. 40 G0 lulverizing propcit O A X i O O Fusing to (il'lllll... None None None, A little Exist None None None None A little ("hargcability 1 1 1 Fixing tempera! ui'e 195 180 170 165 160 105 170 175 195 215 Maximum density of formed (OiOl' 0. 6 0.75 1.00 1.05 l. 01 0.81 1.01 1.00 1.05 1.02 Density of fog 0. 02 0. 03 0. 01 0. 05 0.07 0. 02 0. 03 0. O3 0. 05 O. 07 H111 None None. None A little Exist None None None None A little Resolving power O O O O O O To! all evalual ion O A A O O A TABLE 1) Experiment numbcr 127 128 120 130 131 132 133 134 135 136 13-125, parts 70 70 70 70 70 70 70 70 70 70 Lourio rlorlccylamitlo, parts 5 10 20 30 40 15 15 15 15 15 (EVL, parts 30 30 30 30 30 5 10 20 40 60 lnlverizing proport y O A X O O Fusing to drum h A little A 11111310 A 111.118 A 111.010 EXiS'C NOHB NOIIB N011? NOllO A Li/1G hargeability .1 1 1"- Fixing mppyatuyv 200 185 175 170 200 220 Maximum density 01 formed eolor 0.55 0.81 1.01 1.03 1.05 0.80 1.01 1.00 ,1. 00 1.02 Density of fog 0. 02 0. 03 0. 01 O. 05 0. 07 0. O2 0. 03 0. 03 0. 05 0. 07 Blur" None None None. A little None None None None None A little Resolving power. O O O O O O Total evaluation O A A O O A The above results indicate that increase in addition amount of a charge controlling resin (styrene polymer and the like) to a color forming auxiliary agent results in lowering of color forming efficiency and low temperature fixing efficiency so that any satisfactory image can not be obtained. As the added amount of a color forming auxiliary agent increases to the charge controlling resin, the controlling effect is lowered and blur is formed at detailed portion of image and image quality is lowered though low temperature fixation proceeds further.

As the added amount of a color forming agent (A) increase to a charge controlling resin, the controlling effect is lowered in a manner similar toa color forming auxiliary agent and the color forming efficiency is not increase so much.

Surface of a photosensitive member or image receiving sheet used in this invention is treated with a color forming agent (B), and if desired, a mixture with a color forming auxiliary agent and a binder.

These color forming agent (B) and a mixture with a color forming auxiliary agent may be applied to aphotosensitive member or image receiving sheet by spraying, electrostatic coating, soaking, fluidizing bed coating, brushing, roll coating and any optional conventional method.

A small amount of a binder may be used for adhering the formulation of the present invention to surface of a photosensitive member or image receiving sheet. Representative binders are styrene-butadiene latex, polyvinylpyrrolidone, acryl latex, PVA, polyvinyl acetate copolymer and mixtures thereof. Conventional additives such as antioxidant, emulsifier, polishing agent, solvent, surfactant, dispersing agent, antifoaming agent, and coloring agent. The amount of binder is preferably less than about 20 percent based on weight of a mixture of a color forming agent (B) and a color forming auxiliary agent since an effective color forming and fixation can be effected when the toner contacts large amount of mixture of color forming agent (B) and color forming auxiliary agent at the surface of the image receiving sheet to which the toner is fixed.

Paper sheet or web is usually used as an image receiving sheet. The paper may be composed of organic or inorganic fiber such as cellulose, modified cellulose polymerizable resin, glass, and asbestos fiber.

1n the following, there are shown experimental examples illustrating effect and function of a color forming auxiliary agent at an image receiving sheet surface.

With respect'to phenol-aldehyde polymer as acidic polymer material and stearic acid as fatty acid at various ratio, there were determined fixing temperature and color forming density. The result is shown in Table 13. 36 This result is almost similar to other polymers and fatty acids.

When a fatty acid such as stearic acid is a little, the color forming and fixing temperature is high. On the contrary, when the ratio of stearic acid increases, stearic acid remarkably penetrates into an image receiving sheet upon melting of stearic acid and the paper becomes transparent. Serious drawback caused by increased amount of stearic acid is that the color forming density is low. The optimum point where low temperature fixation is possible and no transparency occurs and further the color forming density is high is at a ratio of a color forming auxiliary agent to a color forming agent (B) being 5 40 parts, preferably, 10 30 parts: 50 parts. A result of using a solid plasticizer in place of fatty acid is shown in Table 14. Solid plastieizer does not cause transparency even when the amount of solid plasticizer is too much. and the color forming density becomes fairly low.

Optimum ratio of solid plasticizer to color forming agent (B) is 5 40 parts, preferred with 10 30 parts, 50 parts.

stearate increases, there is a drawback that the color forming density is low.

An appropriate addition amount of fatty acid metal salt capable of giving low temperature fixing effect as 5 well as high color forming density ranges from 5 to 40 parts, preferred with from 10 to 30 parts per 50 parts of color forming agent (B).

Table 16 shows a result obtained by using monoglycerol stearate, a kind of fatty acid ester, as color 10 forming auxiliary agent.

The optimum mixing ratio is the same as that for fatty acid.

Table 17 shows a result obtained by using tridecylic acid amide, a kind of fatty acid amide, as color forming l5 auxiliary agent. The optimum ratio is the same as that for fatty acid metal salt.

Table 18 shows a result in case of using diphenylbutyric acid as color forming agent (B).

Table 13 Phenol-Aldehyde Polymer 50 50 50 5O 50 50 50 50 50 (color forming parts parts parts parts parts parts parts parts parts agent B) Stcaric acid (color forming do. do. do. 20 do. do. do. do. do. do. auxiliary agent) Styrene-Butadiene Latex 20 do. 20 do. 20 do. 20 do. 20 do. 20 do. 20 do. 20 do. 20 do. (Dow 686) Water do. 150 do. 150 do. 150 do. 150 do. 150 do. 150 do. 150 do. 150 do Sodium salt of treated resin 0.4 do. 04 do. 0.4 do. 0.4 do. 0.4 do. 0.4 do. 0.4 do. 0.4 do. 0.4 do. (Dresinate X) C .V.L. 280C 270C 240C 200C 190C 170C C 160C 160C Fixing toner Temper- C VL+ ature styrene 270 260 240 200 180 160 160 160 toner lmage density 1.2 1.2 1.2 1.1 1.1 0.9 0.8 0.8 0.8 high high good good good An An An An color color image image image image image image image Note forming forming receivreceivreceiv receivtempertempering ing ing ing aturc. ature. sheet sheet sheet sheet good good becomes becomes becomes becomes image image transtranstranstransparent parent parent parent Table 14 Phenol- Aldehyde v Polymer 50 50 5O 5O 50 50 5O 50 50 (color forming parts parts parts parts parts parts parts parts parts agent B) EGDB (color forming 0 do. 5 do. 10 do. 20 do. 30 do. 40 do. 50 do. 60 do. 70 do. auxiliary agent) Styrenc-Butadiene Latex 20 do. 20 do. 20 do. 20 do. 20 do. 20 do. 20 do. 20 do. 20 do. (Dow 686) Water 150 do. 150 do. 150 do. 150 do. 150 do. 150 do. 150 do. 150 do. 150 do. Sodium salt of treated rosin 0.4 do. 0.4 do. 0.4 do. 0.4 do. 0.4 do. 0.4 do. 04 do. 04 do. 0.4 do. (Dresinate X) C .V.L. 280C 270C 260C 2 10C 190C 1 80C 160C 160C 160C Fixing toner Temper- CVL+ ature styrene 270 260 250 200 180 170 150 150 150 toner Image density 1.2 1.2 1.2 1.1 1.0 0.8 0.6 0.6 0.6 I high high high good good low low low low color color color image image Image image 1 image image Note forming forming forming density density dCnSl1) density tempertempertemper ature. ature. ature. good good good image image image Table 15 Phenol-Aldehyde Polymer 50 50 50 50 50 50 50 5O 50 (color forming parts parts parts parts parts parts parts parts parts agent B) Aluminum stearate (color forming do. do. do. do. do. do. do. do. do. auxiliary agent) Styrene-Butadiene Latex 20 do. 20 do. 20 do. 20 do. 20 do. 20 do. 20 do. 20 do. 20 do. (Dow 686) Water do. 150 do. 150 do. 150 do. 150 do. 150 do. 150 do. 150 do. 150 do. Sodium salt of treated rosin 0.4 do. 0.4 do. 0.4 do. 0.4 do. 0.4 do. 0.4 do. 0.4 do. 0.4 do. 0.4 do. (Dresinate X) (.V.L 280C 270C 240C 200C 190C 170C C 160C 160C Fixing toner Temper- C VL+ uture styrene 270 260 240 200 180 160 160 160 toner Image density 1.2 1.2 1.2 1.1 1.1 0.8 0.7 0.7 0.7 high high good good good low low low low color eolor image image image image image image image Note forming tormmg density density density density tempertemperature. ature. good good image image Table 16 Phenol-Aldehyde Polymer 50 50 50 50 50 50 50 50 50 (color forming parts parts parts parts parts parts parts parts parts agent B) Monoglyeeral stearate 0 do. 5 do. 10 do. 20 do. 30 do. 40 do. 50 do. 60 do. 70 do. (color forming auxiliary agent) Styrene-Butadiene Latex 20 do. 20 do. 20 do. 20 do. 20 do. 20 do. 20 do. 20 d0. 20 do. (Dow 686) Water 150 do. 150 do. 150 do. 150 do. 150 do. 150 do. 150 do. 150 do. 150 do. Sodium salt of rosin 0.4 do. 0.4 do. 0.4 do. 0.4 do. 0.4 do. 0.4 do. 0.4 do. 0.4 do. 0.4 do.

C .V.L 280C 270C 200C 1 90C 160C 1 60C 1 60C 1 60C 1 60C Fixing toner Temper- C VL+ ature styrene 270 260 200 180 150 150 150 150 150 toner Dnox 1.2 1.2 1.2 1.2 1.2 0.9 0.8 0.8 0.8 high high high high high low low low low color color color color color image image image image Note forming forming forming forming forming density density density density tempertempertempertemper temper ature. ature. ature. ature. ature. high high low low low fixing fixing fixing fixing fixing tempertempertempertempertemperature ature aturc ature ature Table 17 Phenol-Aldehyde Polymer 50 50 50 50 50 5O 50 50 50 (color forming parts parts parts parts parts parts parts parts parts agent B) Tridecylic acid amide 0 do. 5 do. 10 do. 20 do. 30 do. 40 do. 50 do. 60 do. 70 do. (color forming auxiliary agent) Styrene'Butadiene Latex 20 do. 20 do. 20 do. 20 do. 20 do. 20 do. 20 do. 20 do. 20 do. (Dow 686) Water 150 do. 150 do. 150 do. 150 do. 150 do. 150 do. 150 do. 150 do. 150 do. Sodium salt of treated rosin 0.4 do. 0.4 do. 0.4 do. 0.4 do. 0.4 do. 0.4 do. 0.4 do. 04 do. 0.4 do. (Dresinatc X) C .V 1 280C 270C 260C 210C C 180C 160C 160C 160C Fixing toner Temper- C VL+ ature styrene 270 260 250 200 1140 170 150 150 150 toner Image density 1.2 1.2 1.2 1.1 1.0 0.8 0.6 0.6 0.6 4 high high high good good low low low low color color color image image image image image image Note forming forming forming density density density density tempcrtempcrtemperature. ature, aturc. good good good image image image Table 18 DPBA (color forming '50 I 50 50 50 50 50 50 50 5O agent B) parts parts parts parts parts parts parts parts parts Stearic acid (color forming do. do. do. do. do. 40 do. do. do. do. auxiliary agent) Styrcne-Butadiene Latex 20 do. 20 do. 20 do. 20 do. 20 do. 20 do. 20 do. 20 do. Dow 686) Water do. 150 do. 150 do. 150 do. I50 do. 150 do. 150 do. 150 do. 150 do. Sodium salt of treated-rosin 0.4 do. 0.4 do. 0.4 do. 0.4 do. 0.4 do. 0.4 do. 0.4 do. 0.4 do. 0.4 do. (Dresinate X) C .V.L. 230C 270C 240C 200C 190C 170C C 160C 160C Fixing toner Temper- CVL+ ature styrene 270 260 240 200 I80 160 160 160 toner lmage density 1.2 1.2 1.2 1.1 1.1 0.9 0.8 0.8 0.8"

' high high good good good An An An An color color image image image image image image image Note forming forming reccivreceivreceivreceivforming forming ing ing ing ing ature. ature. sheet sheet sheet sheet good good becomes becomes becomes becomes image image transtranstranstransparent parent parent parent and Dresinate X on a high quality paper in the thick- 30 ness of 2 3 microns. The image density shows an optical density, and CVL is Crystal Violet Lactone.

1n the image receiving sheet of the present invention, a mixture of a color forming agent (B) and a color forming auxiliary agent may be added to the paper at an optional step of paper making. In case of coating the mixture, the resulting coating containing a mixture of a color forming agent (B) and a color forming auxiliary agent of2 20 g., preferred with 5 10 g. (as solid) per 1 m can lower the color forming and fixing temperature to a great extent. An amount lessthan that range also has such effect, but results in low color forming density and irregular coating. On the contrary, when an amount more than that range is used, the fixing temper- 4 ature increases and curl occurs.

When a mixture of a color forming agent (B) and a color forming auxiliary agent is incorporated in paper during beater step or is impregnated in paper after the web is formed, a fairly large amount of the mixtureshould be present at the surface of paper sheet. In this case, a good result is obtained when the mixture of 10 20 g. per 1 m of an image receiving sheet is applied to the image receiving surface as a surface coating.

An'example of a printing process using an electrophotographic method of the present invention is explained below. i

There may be used, as a printing master sheet, a developed image which is obtained by developing an electrostatic latent image on an electrophotographic photosensitive member with a toner containing a color forming agent (A) of the present invention. Further, an image obtained by transferring to a transferring member may be also used as a printing master sheet." The master sheet is connected with an image receiving sheet containing a color forming agent (B) and heated to cause a thermal color forming reaction of a color forming agent (A) with a color forming agent (B) resulting in a visible image. This process can be repeatedly conducted by using a new image receiving sheet to produce many sheets of reproduction.

Referring to the drawing, the above process is explained further in detail. A master sheet is prepared by forming an image containing a color forming agent'( A) on a surface of a support such as paper, film, electrophotographic photosensitive plate and the like. Referring to FIG. 4, there is illustrated an embodiment of a master sheet. A toner image 12 containing a color forming agent (A) is formed on a paper, film or electrophotographic photosensitive plate 11.

Referring to FIG. 5, there is shown a printing member in which a color forming agent (B) layer 13 is provided on an appropriate support 14 such as paper, cloth, film and the like. A

'Referring to FIG. 6, the master sheet in FIG. 4 and the printing member in .FIG. 5 are used for reproduction. A master sheet 11, 12 is placed on a plate 17 and a printing member l3, 14 is placed on the master sheet by facing the color forming agent (B) layer to the toner 7 image of the master sheet. A box 15 composed of glass or a thermally conductive material provided with a heater 16 such as infrared ray heater, nichrome wire 0 heater and the like is pressed to the'printing member.

Thus, a thermal reaction is caused to produce color forming images 18 as shown in FIG. 7. In other words, a part of image containing a color forming agent (A) is absorbed into a layer containing a color forming 5 agent (B) of the printing member, transferred thereto and a color forming reaction occurs to form a colored image by pressing and heating. Further, many reproduction can be obtained by repeating the abovementioned procedure. 1

Images containing a color forming agent (A) may be produced by various methods. For example, an image ment by a liquid developer composed of toner containing a color forming agent (A) dispersed in an isoparaffin high insulating liquid". The resulting toner images produced on the zinc oxide paper is used as a master sheet. The light image as used in the above procedure for exposure is a mirror image with respect to the origi nal image.

A photoconductive layer of a photoconductive selenium photosensitive drum or a photoconductive zinc oxide photosensitive drum is charged and exposed by a known method and developed with dry developer by a known magnetic brush or cascade developing method. The resulting toner image can be used as a master sheet, or the toner image transferred to an other sheet may be used as a master sheet.

A photoconductive selenium photosensitive plate or photoconductive zinc oxide layer is charged, exposed by a known method, and developed with a toner containing a color forming agent (A) dispersed in an isoparaffine high insulating carrier, and the image thus developed or the developed image further transferred to an other sheet can be used as a master sheet.

A selective discharging is applied to a photoconductive layer, such as selenium layer, having an insulating film, and a dry or liquid developer containing a color forming agent (A) is used for development. The resulting toner image can be used as a master sheet.

According to the above printing methods, it is possible to produce many sheets of multicolor printing. In a recording method using a thermal color forming reaction of a color forming agent (A) with a color forming agent (B), a plurality of master sheets corresponding to spectrally divided color which has a toner image containing a color forming agent (A) capable of producing a color corresponding to each spectral color. These master sheets are sequentially pressed to a printing member having a color forming agent (B) containing surface and heated by heating at least one of the master sheet and the printing member.

An example of color heat sensitive printing method is as shown below. Master sheets are prepared by an electrophotographic means. In usual, three master sheets i.e., red, blue and green master sheets, corresponding to three divided visible spectra, are prepared.

First photoconductive photosensitive layer sheet after charged is exposed to a light image through a red filter and developed with a color forming agent (A) capable of giving cyan color. Second photoconductive photosensitive layer sheet after charging is exposed to a light image through a green filter and developed with a color forming agent (A) capable of giving magenta color. Third photoconductive photosensitive layer sheet after charging is exposed to a light image through a blue filter and developed with a color forming agent (A) capable of giving yellow color. The resulting three sheets are used as master sheets. Then, these three master sheets are sequentially pressed to a printing paper containingacolor forming agent (B) and heated by using anapparatus as shown in FIG. 6. According to the above mentioned method, fusing color forming is effected by heatingso that a mixed color can be obtained since the later formed color does not suppress theformer formed color. r

According to the above mentioned method, a complicated and expensive printingrnachih'e-is not-necessary, and many sheets of reprodu'etioncan be easily and quickly obtained.

The resulting printed matter is of high density and good quality.

A color forming agent (A) and a color forming agent (B) are usually separated from each other so that the 5 printed matter is stable against light and heat as compared with conventional heat sensitive reproduction.

The following examples are given for illustrating the present invention, but should not be construed as limiting the present invention.

EXAMPLE 1 V Crystal Violet lactone was ground into a particle size I; of 1 50 microns, preferably, 5 20 microns-, by an attritor. The particles over 325 mesh sieve was removed from the toner material .by sieving. To 'the resulting toner was added iron powder at a ratio of 8 -50 weight parts, preferably, 10 weightparts; per one part of the toner. The iron powder was 20. 70 microns, preferably, 40 microns in particle size. A negative charge was applied uniformly to the whole surface of a photoconductive zinc oxide, and then the surface was exposed to a light pattern to produce an electrostatic latent image. The latent image was developed with the mixture of iron powder and toner, by means or magnetic brush in a developing apparatus. The toner particles adhered to the negatively charged image portion.

The phenolic resin (available as trade name, Tainanol 510 from Arakawa Rinsan K.K.; mp. 80f C)'was mixed andground with a suitable binder,.-e.g styrenebutadiene-latex rubber. The mixture was applied onto a paper to form a coating of about 5 microns thick; The sheet thus formed was used as an image receiving sheet.

The toner image was transferred to the image receiv- EXAMPLE 2 Malachite Green lactone (MGL) was used as a toner and iron powder as a carrier.

A photoconductive drum having a selenium layer as a photosensitive member was subjected to charging and exposure by a conventional technique and developed with the above-prepared developing agent by a magnetic brush. The toner particles adhered to the image portion negatively charged.

P-tert-amyl phenol was mixed and ground with styrene butadiene latex, and polyvinyl pyrrolidone in water by a ball-mill. The resulting mixture was applied to a paper to form a coating of about 5 microns thick. The sheet thus formed was used as an image receiving sheet. The toner image on a selenium drum was transferred to the image receiving sheet, followed by sub- 65 jecting to heat color forming fixing. The green image was obtained where a color forming fixing temperature was about 180 C, and color formation initiated at about I 10 C.

EXAMPLE 3 Rhodamine in leuco-base (RL) was used as a toner, and iron powder as a carrier. The process was similar to that of Example 2. and the image receiving sheet was that of Example 1. The color forming fixing temperature was 180 C to result in a red image.

EXAMPLE 4 EXAMPLE 5 80 Parts of Crystal Violet lactone (CVL) was dissolved in 20 parts of myristic acid, and fused. The melted mixture was poured into a shallow pan to cool and solidify. The material was ground in an attritor into a size of l 50 microns, preferably, 5 20 microns.

The particles over 325 mesh sieve was removed from the toner. To the thus sieved toner was added an iron powder at a ratio of 8 50 weight parts, preferably, 10

- weight parts per one weight part of the toner. The iron particles were the range of 20 75 microns, preferably, 40 microns in size. The mixture of iron particles and the toner were introduced into a magnetic brush type developing apparatus. The whole surface of photoconductive zinc oxide was negatively charged, and exposed to a light pattern to form a latent image, which was developed by a developing apparatus. The toner particles adhered to the image portion negatively charged. The above formed toner image was transferred to an image receiving sheet having a coating made from a phenolic resin with a suitable binder. Then, heat color forming fixing was carried out.- The toner comprising 80 parts of CVL and 20 parts of-myristic acid can be fixed at about 1 10,C while the toner EXAMPLE 6 Toner: CVL 80 parts, palmitic acid 20 parts Carrier: iron powder Color forming fixing temperature: 1 10 C EXAMPLE 7 Toner: Malachite Green lactone (MGL) 50 parts,

' an image receiving sheet having a coating of phenolic Stearic acid 50 parts Carrier: iron powder Color forming fixing temperature: C

EXAMPLE 8 Toner: benzoyl leuco methylene blue (BLMB) 95 parts, erucic acid 5 parts Carrier: iron powder Color forming fixing temperature: 1 10 C EXAMPLE 9 Toner: Leuco-auramine 50 parts, behenic acid 50 parts Carrier: iron powder Color forming fixing temperature: C

EXAMPLE l0 Toner: Rhodamine in leuco-base 50 parts, diacetone acryl amide (DAAM) 50 parts Carrier: iron powder Color forming fixing temperature: 90 C EXAMPLE 1 l Toner: CVL 50 parts, ethylene glycol dibenzoate 50 parts Carrier: iron powder Color forming fixing temperature: 100 C EXAMPLE l2 Toner: Malachite Green lactone (MGL) 30 parts, di-

cyclohexyl phthalate (DCHP) 60 parts Carrier iron powder Color forming fixing temperature: 1 10 C EXAMPLE 13 Toner: Crystal Violet lactone (CVL) 50 parts, Rhodamine in leuco-base 50 parts Carrier: iron powder Color forming fixing temperature: C

Color: purple EXAMPLE l4 80;Parts of 8-methoxy indolino spiropyrane and 20 parts of stearic acid were mixed and fused. The fused mixture was poured into a pan to cool and solidify. The solidified material was crushed by a hammer mill crusher, and then ground by a jet mill into fine powder of a size having 1 50 microns, preferably, 5 20 microns. lron powder was added to the thus formed toner at a ratio of 8 50 weight parts, preferably, l0 20 weight parts per one part of the toner. The iron powder was 20 75 microns, preferably, 25 40 microns in size. The mixture of iron powder and toner, i.e., the developing agent was introduced into a developing apparatus of magnetic brush type. The whole surface of photoconductive zinc oxide was negatively charged, and exposed to a light and dark pattern to form a latent image, which was developed by a developing apparatus. The toner adhered to the image portion negatively charged.

Then, the toner image thus formed was transferred to resin with suitable binder. The heat color forming fixing was carried out. The toner comprising 80 parts of 8 '-methoxy indolino spiropyrane and 20 parts of stearic acid fixed at a temperature of about 1 C to result in a dark blue image.

EXAMPLE 70 Parts of styrene resin (available as a trade name Piccolastic D-125 from Esso Standard Oil), 15 parts of stearic acid, parts of Crystal Violet lactone (CVL) and 20 parts of Erogyl No. 200 (silica available from Nippon Erogyl) were mixed and fused. and then ground by a jet mill into a size below 5 microns to produce a toner. To 100 g. of the toner was added 1 l of lsopar (trade name; petroleum solvent available from Esso Standard Oil), and ground for a period of 1.5 hours by means of an attritor, into particles having a size of 1 2 microns. To 50 ml. of this concentrated liquid was added 2 l of lsopar H and sufficiently ground to prepare a developing agent.

Following the electrophotographing process disclosed in Japanese Patent Publication No. 23910/1967, a latent image was formed on an insulating layer and developed with the developing agent thus produced to form a toner image.

Styrene-butadiene copolymer latex 20 weight as a binding agent, Dresinate X (available from Hercules Corp.) 0.3 weight as an emulsifier, and phenolic aldehyde polymer (of fine particles of about 1 3 microns in size) 79.7 weight as a color forming agent (B) were dispersed in water, and applied to a high quality paper to form a dried coating of 10 g. per square meter. On the formed receiving sheet was the powder image transferred, and heated at about 180C to completely fix the image on the sheet. The resultant image was blue and clear. This image could not be vanished even when rubbed with a rubber eraser.

EXAMPLE 16 70 Parts of styrene resin (trade name Piccolastic D-l vavailable from Esso Standard Oil, mp. 90 l25C), 15 parts of palmitic acid and 20 parts of Rhodamine lactone (available from Hodogaya Chemical Co., Ltd.) were mixed and ground in a vibrating mill crusher. The mixture was uniformly melted, followed by cooling to solidify. The solid mixture was crushed by hammer mill crusher, and ground with ajet mill crusher into the particles of the size of 1 50 microns, preferably, 5 20 microns. To the afforded powder, i.e., the toner, was added iron powder i.e. a carrier and mixed at a ratio of 3-- weight parts, preferably, 5 10 weight parts per one part of the toner. The carrier was 20 75 microns, preferably, 25 50 microns in particle size. In the mixture of the carrier and the toner, that is, in the developing agent, the carrier was positively charged and the toner was negatively charged.

To a polyethylene terephthalate film (100 microns thick) undercoated with gelatine was applied a quarternary ammonium polymer (trade name CP-261, available from Calgon Corp.) to impart conductivity, and sufficiently dried. Further, to this coating was applied a 5 solution of polyvinyl carbazole in monochlorobenzene solvent sensitized with Crystal Violet by a roller to form a photoconductive coating. Still further, an 8 solution of polyvinyl carbazole 10 parts and phenolic aldehyde polymer 8 parts in monochlorobenzene solvent was applied-to the photoconductive film thus formed by a roller to form a coating of 4 6 g. per square meter.

The photoconductive film was uniformly charged with a corona discharger, and then, exposed to a light pattern to form a latent image, which was developed by the toner. The afforded powder image was melt-heated to result in a red and complete image. This image was appropriate for an overhead projector.

EXAMPLE 17 Parts of styrene resin (trade name Piccolastic D- 125, available from Esso Standard Oil; softing point 90- 125C), 15 parts of myristic acid and 20 parts of Malachite Green lactone (MGL) were mixed and ground in a vibrating mill crusher. The mixture was uniformly melted to cool into solid. The solid mixture was crushed by a hammer crusher, and then, ground with a jet mill crusher into the particles of 1 50 microns, preferably, 5 20 microns in size. To the produced fine powder, that is, the toner, was added iron powder, that is, a carrier at a ratio of 3 30 weight parts, preferably, 5 10 weight parts per one part of the toner. The carrier was 20 microns, preferably 25 50 microns in particle size. In the mixture of the carrier and the toner, that is, in the developing agent, the carrier was positively charged and the toner negatively charged.

The latent image produced on an insulating layer by the electrophotographic process disclosed in Japanese Patent Publication No. 24748/1968 was developed with the developer produced above by means of magnetic brush technique to form a toner image.

Styrene butadiene copolymer latex 20 weight 7: as a binder, Dresinate X (available From Hercules Corp.) 0.3 weight as an emulsifier and rosin-modified maleic acid polymer (fine powder) 79.7 weight as a color-forming agent (B) were dispersed in water, and the dispersion mixture was applied to a high quality paper of 50 -60 g./m to form a dried coating of 10 g. per square meter. To the receiving sheet thus produced was transferred the powder image and heated at a temperature of about 180C to result in a green sharp image with complete fixation. The resultant image was not erased when rubbed vigorously with a rubber eraser.

EXAMPLE 18 70 Parts of styrene resin (trade name, Piccolastic D- 125, available from Esso Standard Oil; softening point C), 15 parts of stearic acid, 9 parts of Crystal Violet lactone (CVL), 8 parts of Rhodamine lactone (RL), 8 parts of Malachite Green lactone (MGL) and 9 parts of leuco auramine were mixed and ground in a vibrating mill crusher. The mixture was uniformly melted and cooled to solidify.

The solid mixture was crushed by a hammer mill crusher, and then, ground by a jet mill grinder into a particle size of 1 50 microns, preferably, 5 20 microns. To the afforded fine powder was added an iron powder i.e. a carrier at a ratio of 3 30 weight parts, preferably, 5 10 weight parts per one weight part of the toner. The carrier was 20 75 microns, preferably 25 50 microns in particle size. In this mixture of the carrier and the toner, that is, in the developing agent, the carrier was positively charged and the toner negatively charged.

The electrostatic latent image produced by charging uniformly a photoconductive surface of selenium deposited on an aluminum plate and exposing the surface to a light pattern was developed by the developer thus produced to form a toner image. The toner image was EXAMPLE 19 70 parts of styrene-methyl ester of acrylate copolymer (in a. inolar ratio of 6 4) (softening point l OO- I 3QC), 15 parts of montanic acid, and 20 parts of Crystal Violet lactone (CVL) were mixed and ground by: a vibrating mill grinder. The mixture was sufficiently fused and cooled to solidify. The solid material wash cr'us hed by a hammer mill crusher and ground by a jet mill grinder into the particle size of l 50 microns, preferably, 5 20 microns. To the resulting toner was added an iron powder, i.e., carrier at a ratio of 3 30 weight parts, preferably, 5 weight parts per one part ofthe toner. The carrier was 75 microns, preferably, 2 5 50 microns in a particle size. The carrier .was positively charged and the toner negatively charged in the mixture of carrier and toner, i.e., a developing agent.

A corona charge was applied uniformly to a photoconduc'tive member prepared by depositing selenium on an aluminium plate, and then the member was exposed tea light pattern to form an electrostatic latent image, which was developed with the above produced developing agent to form a toner image. The toner image. was transferred on a transferring sheet which wasprepared by the process wherein 10 parts of ethylene-maleic anhydride copolymer hydrolyzed product was dissolved in 100 parts of methyl ethyl ketone, and

the solution soaked in a high grade paper at the ratio of 5 g./m The transferring sheet was heatedat about l80C to form blue color in the portion where the toner image was transferred. The resultant copy was clear and completely fixed. The resultant image was not vanished when rubbed strongly with an eraser.

EXAMPLE 20 Seventy parts of copolymer of styrene maleic acid methyl ester of acrylate (6:l.5:2.5 mole,- softening point 95-135C), 20 parts of stearic acid and 20 parts of Crystal Violet Lactone (CVL) were mixed and ground by a vibrating mill grinder. The said mixture was sufficiently fused and cooled to solidify.

The said solidified material was crushed by a hammer mill crusher, and then ground a jet mill grinder until the particle size became l-50 microns, preferably 5-20 microns.

One weight part of the said fine powder (i.e. toner) was mixed with 3-30 weight parts, preferably 5-10 weight parts, of an iron powder, i.e. carrier.

The particle size of the said carrier is 20-75 microns, preferably -50 microns.

The carrier was positively charged and the toner was charged negatively in the mixture of the said carrier aluminium plate was developed by the above mentioned developing agent to form a toner image. The said toner image was transferred to 'a transferring paper prepared by coating a composition obtained by dispersing 20 weight of styrene-butadiene copolymer latex as a binder and 0.3 weight of Dresinate X (trade mark, manufactured by Hercules Co.) as an emulsifier and 797 weight of carboxy polyethylene polymer hydrolyzed product (a finely devided material) as a color forming agent (B) in water on a high gradepaper (5'0 -60 g./m until the weight of a dried solid ofthe said material became 5 g., was heated at about l40C and a portion to which the toner image was transferred formed blue color, and as the result, a completely fixed clear copy was obtained. The said image was nomad; ished at all by strong rubbing.

EXAMPLE 21 Seventy parts of copolymer resin of vinyl chloride and vinyl acetate (in a ratio of 91 molar and,9 molar 30 parts of stearic acid and 20 parts of Crystal Violet Lactone (CVL) were mixed and ground by a vibrating mill grinder. The said mixture was sufficiently fused andcooled to solidify.

' The said solidified material was crushed by a hammer mill crusher, and then ground ajet mill grinder until the particle size became 1-50 microns, preferably 5-20 microns.

One weight part of the said fine powder (i.e. toner) was mixed with 3-30 weight parts, preferably 5-10 weight parts, of an iron powder, i.e. carrier. I

The particle size of the said carrier is 20-75 microns, preferably 25-50 microns.

The carrier was positively charged and the toner was charged negatively in the mixture of the said carrier and toner, i.e. a developing agent.

Then the electrostatic latent image obtained by corona-charging and applying a light pattern to a photoconductor layer composed of ZnO binder was developed by the above mentioned developing agent to form a toner image. The said toner image was transferred to a transferring paper prepared by coating a composition obtained by dispersing 20 weight of styrene-'butadien copolymer latex as a binder and 0.3 weight of Dresinate X (trade mark, manufactured by Hercules Co.) as an emulsifier and 797 weight of vinyl methyl ether maleic anhydride copolymer hydrolyzed product (a finely divided material) as a color forming agent (B) in water on a high grade paper (50 -60 g/m2) until the weight of a dried solid of the said material became to 7 g., was heated at about 180C and a portion to which the toner image was transferred formed blue color, and as the result, a completely fixed clear copy was obtained. The said image was not vanished at all by strong rubbing.

EXAMPLE 22 Seventyparts of vinyl chloride-propylene copolymer (:30 molar 7:), 20 parts of lacceric acid and 30 parts of Crystal Violet Lactone (CVL) were mixed and ground by a vibrating mill grinder. The said mixture was sufficiently fused and cooled to solidify.

The said solidified material was crushed by a hammer mill crusher, and-then ground-by a jet mill grinder until the particle size became l-50 microns, preferably 5-20' microns.

One weight part of the said fine power.(i.e.. toner) was mixed with 3-30 weight parts, preferably 5-10 weight parts, of an iron powder, i.e. carrier.

The particle size of the said carrier is 20-75 microns, preferably 25-50 microns. t

The carrier was positively charged and the toner was charged negatively in the mixture of the said carrier and toner, i.e. a developing agent.

1.0 Part of acrylic resin, 4 parts of zinc oxide and 2 parts of phenol-aldehyde polymer were dispersed together with xylene-toluene (50:50) mixture solvent in a ball mill for a period of 24 hours, further the addition of the above solvent until the viscosity of 80-100 c.p. to form a coating liquid. The coating liquid was applied to ZnO-acrylic resin sheet to form a coating of 4 5 g/m2. A corona charging was applied to this ZnO sheet, further exposed to a light pattern to form an electrostatic latent image, which was developed with the above toner. The obtained powder image was heated at the temperature of about 180C to result in a blue image with complete fixing.

EXAMPLE 23 Seventy parts of styrene resin (Piccolastic D-l manufactured by ESSO Standard Oil Co.) 15 parts of .stearic acid and 30 parts of 8'-methoxy indolino spiropyrane were mixed and ground by a vibrating mill grinder. The said mixture was sufficiently fused and cooled to solidify.

The said solidified material was crushed by a hammer mill crusher. and then ground by ajet mill grinder until the particle size became l-50 microns, preferably -20 microns.

One weight part of the said fine powder (i.e. toner) was mixed with 3-30 weight parts, preferably 5-10 weight parts, of an iron powder, i.e. carrier.

The particle size of the said carrier is 20-75 microns, preferably 25-50 microns.

The carrier was positively charged and the toner was charged negatively in the mixture of the said carrier and toner, i.e. a developing agent.

Then the electrostatic latent image obtained on the insulating layer by the electrophotography process disclosed in Japanese Patent Publication No. 23910/1967 was developed by the above mentioned developing agent by means of magnetic brush technique to form a toner image. The said toner image was transferred to a transferring paper prepared by coating a composition obtained by dispersing 20 weight of styrene-butadien copolymer laten as a binder and 0.3 weight of Dresinate X (trade mark, manufactured by Hercules Co.) as an emulsifier and 797 weight of carboxy polyethylene polymer (a finelly divided material) as a color forming agent (B) in water on a high grade paper (50-60 g/m2 until the weight ofa dried solid of the said material became to g., was heated at about 180C and a portion to which the toner image was transferred formed dark blue color, and as the result, a completely fixed clear copy was obtained. The said image was not vanished at all by strong rubbing.

EXAM PLE 24 Seventy parts of styrene resin (Piccolastic D-100 manufactured by ESSO Standard Oil Co.), 15 parts of lacceric acid and parts of 6.6'-diamino spiro (phthalane 1.9 xanthene) were mixed and ground by a vibrating mill grinder. The said mixture was sufficiently fused and cooled to solidify.

The said solidified material was crushed by a hammer mill crusher, and then ground by ajet mill grinder until the particle size became 1-50 microns, preferably 5-20 microns.

One weight part of the said fine powder (i.e. toner) was mixed with 3-30 weight parts, preferably 5-10 weight parts, of an iron powder, i.e. carrier.

The particle size of the said carrier is 20-75 microns, preferably 25-50 microns.

The carrier was positively charged and the toner was charged negatively in the mixture of the said carrier and toner, i.e. a developing agent.

Then the electrostatic latentimage obtained on an insulating layer by the electrophotography process disclosed in Japanese Patent Publication No. 23910/1967 was developed by means of magnetic brush technique by the above mentioned developing agent to form a toner image. The said toner image was transferred to a transferring paper prepared by coatinga composition obtained by dispersing a solution of 10 parts of phenolacetylene polymer in parts of methyl ethyl ketone, in a ratio of 5 g/m2 on a high grade paper was heated at about 195C and a portion to which the toner image was transferred formed red color, and as the result, a completely fixed clear copy was obtained. The said image was not vanished at all by strong rubbing with an eraser.

EXAMPLE 25 Seventy parts of styrene resin (Piccolastic D-l25, manufactured by ESSO Standard Oil Co.), 15 parts of lauric acid and 20 parts of 1,1-bis (p-aminophenyl) phthalan were mixed and ground by a vibrating mill grinder. The said mixture was sufficiently fused and cooled to solidify.

The said solidified material was crushed by a hammer mill crusher, and then ground by a jet mill grinder until the particle size became l-50 microns, preferably 5-20 microns.

One weight part of the said fine powder (i.e. toner) was mixed with 3-30 weight parts, preferably 5-10 weight parts, of an iron powder, i.e. carrier.

The particle size of the said carrie is 20-75 microns preferably 25-50 microns.

The carrier was positively charged and the toner was charged negatively in the mixture of the said carrier and toner, i.e. a developing agent.

Then the electrostatic latent image obtained by corona-charging and applying a light pattern to a photoconductor composed of selenium vacuum deposited on an aluminium plate was developed by the above mentioned developing agent to form a toner image. The said toner image was transferred to a transferring paper prepared by coating a composition obtained by dispersing 20 weight of styrene-butadiene copolymer latex as a binder and 0.3 weight of Dresinate X (trade mark, manufactured by Hercules Co.) as an emulsifier and 79.7 weight of carboxy polyethylene polymer hydrolyzed product (a finely divided material) as a color forming agent (B) in water on a high grade paper (50-60) g/m until the weight of a dried solid of the said material became to 10 g., was heated at about C and a portion to which the toner image was transferred formed purple color, and as the result, a completely fixed clear copy was obtained. The said image was not vanished at all by strong rubbing with an eraser.

EXAMPLE 26 Employing the process of EXAMPLE 15, but substituting for Crystal Violet Lactone (CVL) each N-(2,5- dichrophenyl) leuco auramine, N-acetyl auramine, and dianisylidene acetone, there were obtained the similar result to EXAMPLE l5.

EXAMPLE 27 Employing the process of Example 15, but substituting for styrene resin, each vinyl chloride resin, vinylidene chloride resin, polyethylene, polypropylene, epoxy resin, the toner chargable negatively was produced. There were obtained the similar results to Example l5.

EXAMPLE 28 Seventy parts of styrene resin (Piccolastic D-l25, manufactured by ESSO Standard Oil Co.), 15 parts of lead caprylate and 20 parts of Crystal Violet Lactone (CVL) were mixed and ground by a vibrating mill grinder. The said mixture was sufficiently fused and cooled to solidify.

The said solidified material was crushed by a hammer mill crusher, and then ground by ajet mill grinder until the particle size became l-50 microns, preferably -20 microns.

One weight part of the said fine powder (i.e. toner) was mixed with 3-30 weight parts, preferably 5-10 weight parts, of an iron powder, i.e. carrier.

The particle size of the said carrier is 20-75 microns, preferably 25-50 microns.

The carrier was positively charged and the toner was charged negatively in the mixture of the said carrier and toner, i.e. a developing agent.

Then the electrostatic latent image obtained on an insulating layer by an electrophotography process disclosed in Japanese Patent Publication No. 23910/1967 was developed by the above mentioned developing agent by means of magnetic brush technique, to form a toner image. The said toner image was transferred to a transferring paper prepared by coating a composition obtained by dispersing 20 weight of styrene-butadien copolymer latex as a binder and 0.3 weight of Dresinate X (trade mark, manufactured by Hercules Co.) as an emulsifier and797 weight of carboxy polyethylene polymer (a finely divided material) as a color forming agent (B) in water on a high grade paper (50-60 g/m2) until the weight of a dried solid of the said material became to g., was heated at abot 190C and a portion to which the toner image was transferred formed blue color, and as the result, a completely fixed clear copy was obtained. The said image was not vanished at all by strong rubbing.

EXAMPLE 29 Seventy parts of styrene resin (Piccolastic D-l 25, manufactured by ESSO Standard Oil Co.), parts of aluminum stearate (mp. 105C) and parts of Rhodamine lactone were mixed and ground by a vibrating mill grinder. The said mixture was sufficiently fused and cooled to solidify.

The said solidified material was crushed by a hammer mill crusher, and then ground by a jet mill grinder until the particle size became 1-50 microns, preferably 5-20 microns.

One weight part of the said fine powder (i.e. toner) was mixed with 3-30 weight parts, preferably 5-10 weight parts, of an iron powder, i.e. carrier.

The particle size of the said carrier is 20-75 microns, preferably 25-50 microns.

The carrier was positively charged and the toner was charged negatively in the mixture of the said carrier and toner, i.e. a developing agent.

Then the electrostatic latent image obtained on an insulating layer by the electrophotography process disclosed in Japan Patent Publication No. 23910/1967 was developed by the above mentioned developing agent by means of a magnetic brush technique to form a toner image. The said toner image was transferred to a transferring paper prepared by coating a composition obtained by dispersing 20 weight of styrene-butadien copolymer latex as a binder and 0.3 weight of Dresinate X (trade mark, manufactured by Hercules Co.) as an emulsifier and 797 weight of carboxy polyethylene polymer (a finely divided material) as a coilor forming agent (B) in water on a high grade paper (50-60 g/m2) until the weight of a dried solid of the said material became to 10 g., was heated at about 195C and a portion to which the toner image was transferred formed red color, and as the result, a completely fixed clear coipy was obtained. The said image was not vanished at all by strong rubbing.

EXAMPLE 30 Seventy parts of styrene resin (Piccolastic D-l25 manufactured by ESSO Standard Oil Co.), 15 parts of lead laurate and 20 parts of Malachite Green Lactone were mixed and ground by a vibrating mill grinder. The said mixture was sufficiently fused and cooled to solidify. The said solidified material was crushed by a hammer mill crusher, and then ground by a jet mill grinder until the particle size became l-50 microns, preferably 5-20 microns.

One weight part of the said fine powder (i.e. toner) was mixed with 3-30 weight parts, preferably 5-10 weight parts, of an iron powder, i.e. carrier.

The particle size of the said carrier is 20-75 microns, preferably 25-50 microns.

The carrier was positively charged and the toner was charged negatively in the mixture of the said carrier and toner, i.e. a developing agent.

Then the electrostatic latent image obtained on an insulating layer by the electrophotography process disclosed in Japanese Patent Publication No. 239l0/l967 was developed by the above mentioned developing agent by means of magnetic brush technique to form a toner image. The said toner image was transferred to a transferring paper prepared by coating a composition obtained by dispersing 20 weight of styrene-butadien copolymer latex as a binder and 0.3 weight of Dresinate X (trade mark, manufactured by Hercules Co.) as an emulsifier and 797 weight 7c of rosin modified maleic acid polymer (a finely divided material) as a color forming agent (B) in water on a high grade paper (50-60 g/m2) until the weight of a dried solid of the said material became to 5 g., was heated at about C and a portionto which the toner image was transferred formed green color, and as the result, a completely fixed clear copy was obtained. The said 

1. AN ELECTROPHOTOGRAPHIC METHOD WHICH COMPRISES (I) DEVELOPING AN ELECTRIC LATENT IMAGE FORMED ON A PHOTOSENSITIVE MEMBER COMPRISING A PHOTO CONDUCTIVE MATERIAL CONTAINING A COLOR FORMING AGENT (B) IN A SURFACE FOR FORMING A VISIBLE IMAGE WITH CHARGED TONER PARTICLES CONTAINING A COLOR FORMING AGENT (A) AND A COLOR FORMING AUXILIARY AGENT HAVING A MELTING POINT RANGING FROM 40*C TO 130*C SELECTED FROM THE GROUP CONSISTING OF FATTY ACID, FATTY ACID METAL SALT, FATTY ACID ESTER, FATTY ACID AMIDE, FATTY ACID ANILIDE AND SOLID PLASTICIZER, SAID COLOR FORMING AUXILIARY AGENT ADDED IN THE AMOUNT OF 5-200 PARTS PER 100 PARTS OF SAID COLOR FORMING AGENT (A); AND (II) HEATING TO CAUSE A THERMAL COLOR FORMING REACTION BETWEEN THE COLOR FORMING AGENT (A) IN THE TONER AND THE COLOR FORMING AGENT (B) IN THE PHOTOSENSITIVE MEMBER RESULTING IN THE FORMATION OF A COLORED FIXED IMAGE ON THE PHOTOSENSITIVE MEMBER, THE COLOR FORMING AGENT (A) BEING SELECTED FROM THE GROUP CONSISTING OF
 1. DIARYLPHALIDES,
 1. POLYMER OF PHENOL AND ALDEHYDE,
 2. POLYMER OF PHENOL AND ACETYLENE,
 2. LEUCO AURAMINES,
 2. leuco auramines,
 2. polymer of phenol and acetylene,
 2. leuco auramines,
 2. polymer of phenol and acetylene,
 2. The electrophotographic method according to claim 1 wherein the tonEr particles comprising the coloring agent (A) and the color forming auxiliary agent further comprise a binder resin.
 2. leuco auramines,
 2. polymer of phenol and acetylene,
 2. leuco auramines,
 2. polymer of phenol and acetylene,
 3. rosin modified maleic acid resin,
 3. acryl auramines,
 3. rosin modified maleic acid resin,
 3. acryl auramines,
 3. The electrophotographic method according to claim 1 wherein the photosensitive member comprising a photoconductive material and containing a color forming agent (B) further comprises a binder resin in the surface for forming a visible image.
 3. rosin modified maleic acid resin,
 3. acryl auramines, Alpha , Beta -unsaturated arylketones,
 3. rosin modified maleic acid resin,
 3. acryl auramines,
 3. ACRYL AURAMINES,
 3. ROSIN MODIFIED MALEIC ACID RESIN,
 4. HYDROLYZED PRODUCT OF COPOLYMER OF STYRENE AND MALEIC ANHYDRIDE,
 4. A, B-UNSATURATED ARYLKETONES,
 4. Alpha , Beta -unsaturated arylketones,
 4. hydrolyzed product of copolymer of styrene and maleic anhydride,
 4. hydrolyzed product of copolymer of styrene and maleic anhydride,
 4. The electrophotographic method according to claim 1 wherein the photosensitive member containing the color forming agent (B) includes an auxiliary color forming agent having a melting point ranging from 40*C to 130*C selected from the group consisting of fatty acid, fatty acid metal salt, fatty acid ester, fatty acid amide, fatty acid anilide and solid plasticizer.
 4. Alpha , Beta -unsaturated arylketones,
 4. hydrolyzed product of copolymer of styrene and maleic anhydride,
 4. Alpha , Beta -unsaturated arylketones,
 4. hydrolyzed product of copolymer of styrene and maleic anhydride,
 5. hydrolyzed product of polymer of carboxy polyethylene,
 5. basic monoazo dyestuff,
 5. hydrolyzed product of polymer of carboxy polyethylene,
 5. basic monoazo dyestuff,
 5. The electrophotographic method according to claim 4 wherein the auxiliary color forming agent is added in the amount of 5 to 40 parts per 50 parts of the color forming agent (B).
 5. hydrolyzed product of polymer of carboxy polyethylene,
 5. basic monoazo dyestuff,
 5. hydrolyzed product of polymer of carboxy polyethylene,
 5. basic monoazo dyestuff,
 5. BASIC MONOAZO DYESTUFF,
 5. HYDROLYZED PRODUCT OF POLYMER OF CARBOXY POLYETHYLENE,
 6. HYDROLYZED PRODUCT OF COPOLYMER OF VINYL METHYL ETHER AND MALEIC ANHYDRIDE,
 6. RHODAMINE B LACTAMS,
 6. rhodamine B lactams,
 6. hydrolyzed product of copolymer of vinyl methyl ether and maleic anhydride,
 6. rhodamine B lactams,
 6. hydrolyzed product of copolymer of vinyl methyl ether and maleic anhydride,
 6. An electrophotographic method which comprises (I) developing an electric latent image formed on a visible image forming surface of a photosensitive member, said member comprising a photoconductive material with charged toner particles, said toner particles comprising a color forming agent (A) and an auxiliary color forming agent having a melting point ranging from 40*C to 130*C selected from the group consisting of fatty acid, fatty acid metal salt, fatty acid ester, fatty acid amide, fatty acid anilide and solid plasticizer, said auxiliary color forming agent added in the amount of 5-200 parts per 100 parts of said color forming agent (A); (II) transferring the resulting toner image to an image receiving sheet containing a color forming agent (B), and (III) heating to cause a thermal color forming reaction between the color forming agent (A) in the toner and the color forming agnet (B) in the photosensitive member resulting in formation of a colored fixed image on the image receiving sheet wherein color forming agent (A) is selected from the group consisting of
 6. rhodamine B lactams,
 6. hydrolyzed product of copolymer of vinyl methyl ether and maleic anhydride,
 6. rhodamine B lactams,
 6. hydrolyzed product of copolymer of vinyl methyl ether and maleic anydride,
 7. hydrolyzed product of copolymer of ethylene and maleic anhydride,
 7. polyaryl carbinols,
 7. hydrolyzed product of copolymer of ethylene and maleic anhydride,
 7. polyaryl carbinols,
 7. An electrophotographic method according to claim 6 wherein the toner particles include a binder resin.
 7. hydrolyzed product of copolymer of ethylene and maleic anhydride,
 7. polyaryl carbinols,
 7. hydrolyzed product of copolymer of ethylene and maleic anhydride,
 7. polyaryl carbinols,
 7. POLYARYL CARBINOLS,
 7. HYDROLYZED PRODUCT OF COPOLYMER OF ETHYLENE AND MALEIC ANHYDRIDE,
 8. JAPANESE ACID CLAY,
 8. BENZOINDOLINO SPIROPYRANS,
 8. benzoindolino spiropyrans,
 8. Japanese acid clay,
 8. benzoindolino spiropyrans,
 8. Japanese acid clay,
 8. The electrophotographic method according to claim 6 wherein the image receiving sheet comprising the color forming agent (B) includes a binder resin in the surface for forming a visible image.
 8. benzoindolino spiropyrans,
 8. Japanese acid clay,
 8. benzoindolino spiropyrans,
 8. Japanese acid clay,
 9. bentonite,
 9. phthalans, and
 9. bentonite,
 9. phthalans, and
 9. The electrophotographic method according to claim 6 wherein the visible image forming surface of the photosensitive member comprising the color forming agent (B) further comprises an auxiliary color forming agent having a melting point ranging from 40*C to 130*C selected from the group consisting of fatty acid, fatty acid metal salt, fatty acid ester, fatty acid amide, fatty acid anilide, and solid plasticizeR.
 9. bentonite,
 9. phthalans, and
 9. bentonite,
 9. phthalans, and
 9. PHTHALANS, AND
 9. BENTONITE,
 10. DIATOMACEOUS EARTH,
 10. SPIROPHTHALANS, AND THE COLOR FORMING AGENT (B) BEING SELECTED FROM THE GROUP CONSISTING OF
 10. spirophthalans, and the color forming agent (B) being selected from the group consisting of
 10. diatomaceous earth,
 10. spirophthalans, and the color forming agent (B) being selected from the group consisting of
 10. diatomaceous earth,
 10. The electrophotographic method according to claim 6 wherein the auxiliary color forming agent is added in the amount of 5-40 parts per 50 parts of said color forming agent (B).
 10. spirophthalans, and the color forming agent (B) being selected from the group consisting of
 10. diatomaceous earth,
 10. spirophthalans, and the color forming agent (B) being selected from the group consisting of
 10. diatomaceous earth,
 11. bisphenol compounds containing carboxyl radical in a molecule,
 11. bisphenol compounds containing carboxyl radical in a molecule,
 11. An electrostatic recording method which comprises (I) developing an electric latent image formed on a visible image forming surface of an electrostatic recording paper containing a color forming agent (B) in the visible iamge forming surface with charged toner particles, said particles comprising a color forming agent (A) and an auxiliary color forming agent having a melting point ranging from 40*C to 130*C selected from the group consisting of fatty acid, fatty acid metal salt, fatty acid ester, fatty acid amide, fatty acid anilide, and solid plasticizer, said color forming auxiliary agent added in the amount of 5-200 parts per 100 parts of said color forming agent (A); and (II) heating to cause a thermal color forming reaction between the color forming agent (A) in the toner and the color forming agent (B) in the electrostatic recording paper, resulting in formation of a colored fixed image wherein the color forming agent (A) is selected from the group consisting of
 11. bisphenol compounds containing carboxy radical in a molecule,
 11. bisphenol compounds containing carboxyl radical in a molecule,
 11. BISPHENOL COMPOUNDS CONTAINING CARBOXYL RADICAL IN A MOLECULE,
 12. POLYMERS OF BISPHENOL COMPOUNDS CONTAINING CARBOXYL RADICAL IN A MOLECULE, AND
 12. polymers of bisphenol compounds containing carboxyl radical in a molecule, and
 12. polymers of bisphenol compounds containing carboxyl radical in a molecule, and
 12. polymers of bisphenol compounds containing carboxyl radical in a molecule, and
 12. polymers of bisphenol compounds containing carboxyl radical in a molecule, and
 12. The electrostatic recording method according to claim 11 wherein the toner particles include a binder resin in the surface for forming a visible image.
 13. The electrostatic recording method according to claim 11 wherein the electrostatic recording paper comprising the color forming agent (B) further comprises a binder resin in the surface for forming a visible image.
 13. phenolic material.
 13. phenolic material.
 13. phenolic material.
 13. phenolic material.
 13. PHENOLIC MATERIAL.
 14. The electrostatic recording method according to claim 11 wherein the visible image recording surface of the photosensitive member comprising the color forming agent (B) includes an auxiliary color forming agent having a melting point ranging from 40*C to 130*C selected from the group consisting of fatty acid, fatty acid metal salt, fatty acid ester, fatty acid amide, fatty acid analide, and solid plasticizer.
 15. The electrostatic recording method according to claim 11 wherein the auxiliary color forming agent is added in the amount of 5-40 parts per 50 parts of said color forming agent (B).
 16. A recording method which comprises closely contacting a master sheet containing a toner image, said toner image formed from a color forming agent (A) and an auxiliary color forming agent having a melting point ranging from 40*C to 130*C selected from the group consisting of fatty acid, fatty acid metal salt, fatty acid ester, fatty acid amide, fatty acid anilide, and solid plasticizer, said color forming auxiliary agent added in the amount of 5-200 parts per 100 parts of said color forming agent (A), with a visible Image forming surface containing a color forming agent (B) of an image receiving sheet, and (II) heating to cause a thermal color forming reaction between the color forming agent (A) and the color forming agent (B) resulting in a visible image wherein the color forming agent (A) being selected from the group consisting of
 17. The recording method according to claim 16 wherein the toner includes a binder resin.
 18. The recording method according to claim 16 wherein the image receiving sheet comprising the color forming agent (B) further comprises a binder resin in the surface for forming a visible image.
 19. The recording method according to claim 16 in which the visible image forming surface of the image receiving sheet comprising the color forming agent (B) further comprises an auxiliary color forming agent having a melting point range from 40*C to 130*C selected from the group consisting of fatty acid, fatty acid metal salt, fatty acid ester, fatty acid amide, fatty acid anilide, and solid plasticizer.
 20. The recording method according to claim 16 wherein the auxiliary color forming agent is added in the amount of 5 to 40 parts of the color forming agent (B). 